In recent years, concerns have been raised about a possible link between some types of non-ionizing radiation and cancer. Non-ionizing radiation is low-frequency radiation that does not have enough energy to directly damage DNA, but it may be able to affect live human cells in other ways. Cell phones, as other electrical devices emit non-ionizing radiation. Therefore, cellular network operators are subjected to governmental laws and regulations regarding the level of radiation emitted from their transmitting sources.
In a typical cellular radio system, Base Stations (BSs) and mobile User Equipment units (UEs) communicate voice and data via a Radio Access Network (RAN) to one or more core networks. BSs are typically cellular base stations, which consist of transceivers and antennas. The mobile UEs are mobile devices, such as cellular telephones and laptops with mobile termination. The core network is a central part of a telecom network that provides various services to customers who are connected to it.
The RAN covers a geographical area which is divided into cell areas, each of which is served by a base station. A cell area is a geographical area wherein radio coverage is provided by the radio equipment in the base stations. Each cell is identified by a unique identity, which is broadcasted by the cell. The base station communicates over the air interface (e.g., using radio frequencies) with the mobile UEs within the cell area. In typical RANs several base stations are typically connected (e.g., by landlines or microwave channels) to a Radio Network Controller (RNC). The RNC (also known as a Base Station Controller) supervises and coordinates various activities of the plural base stations connected to it. The RNCs are typically connected to one or more core networks.
The Universal Mobile Telecommunications System (UMTS) is a third generation mobile communication system, which evolved from the Global System for Mobile Communications (GSM), and is intended to provide improved mobile communication services, based on Wideband Code Division Multiple Access (WCDMA) technology. Code division multiple access-based systems use a wider frequency band to achieve the same rate of transmission as FDMA, In a forum known as the Third Generation Partnership Project (3GPP), telecommunications suppliers proposed and agreed upon standards for third generation networks and Universal Terrestrial Radio Access Network (UTRAN) specifically. The UTRAN contains cellular base stations (also known as Node Bs), and Radio Network Controllers (RNCs). The RNC provides control functionalities for one or more Node Bs. Node B contains radio frequency transmitters and receivers used to communicate directly with the mobile UEs, which move freely around it. In this type of cellular network, the mobile UEs cannot communicate directly with each other but have to communicate with the Node B.
Base Stations, which are typically the most radiating source in the cellular system, are subjected to governmental laws and regulations. Thus, Base Stations require an operational permit. The terms of the permit and its requirements are usually based on ICNIRP (International Council on Non-Ionizing Radiation Protection) recommendations regarding the level of radiation and power per transmitter source. The 3GPP forum investigated enhanced ways to control the power of third generation networks with advance measurement. One result of the forum's work is the UTRAN Iur interface Radio Network Subsystem Application Part (RNSAP) signaling, as described in 3GPP TS 25.423 V3.14.2 (2004-07), for example. This standard specifies the radio network layer signaling procedures of the control plane between RNCs in UTRAN, in which the transmitted power is one of those measurements.
Today, enforcing the regulations regarding the level of radiation emitted from the transmitting sources of cellular operators requires periodic measurements of the RF power density at each cellular site. However, such measurements present many technical challenges and difficulties. Protocols for the measurement of RF energy for the purpose of human exposure assessment often recommend the use of an “isotropic broadband probe” because this type of sensor responds, equally to energy arriving from any direction, and over a broad frequency range, as does the human body. These instruments are commonly used because they allow a simple measurement. However, some of the meters used for typical RF compliance surveys are unable to accurately measure the low power densities present at some cellular sites.
A related problem involves the concurrent presence of several signals from different antennas, such that the radiation reading produced by the measuring instrument is a combination of all the signals in the measuring spot. Realistically, this composite measurement of all signals may be the most relevant exposure metric. However, once radiation anomaly is detected, it is required to discover the cause (e.g., antenna power, antenna direction, feeder loss, etc.) for the anomaly. Measuring the radiation in a specific spot fails to indicate the over-power radiating source.
In addition, the measurement must be performed in a time in which radiation anomaly indeed occurs. It is well known that the radiation levels at a cellular site are not always constant. People use their cellular phones more at some times of the day, and on some days of the week, than at others. The cellular service providers maintain additional capacity which becomes active as needed to meet the demands. Each active channel adds to the measured radiation at the cellular site. Thus, the probability to detect the radiation anomaly when performing periodic measurements is relatively low.
Common radiation monitoring methods include radiation intermediate surveys and radiation probes in field stations. Radiation measurement field station is a device capable of measuring the radiation in a site. The radiation measurement field station is typically located in a specific spot in the measured site. However, radiation measurement field stations suffer many drawbacks. They hardly allow repeating similar tests, they don't allow automating the same data collection on large volumes, they require manual collection of data, they make it hard to reference data coming from different sources, and they are very expensive.
In recent years, cellular networks have become more and more complex. As a result, there is a need for a simple and automated operation and maintenance (O&M) method. In order to decrease management costs, to use hardware in the most effective way, and to maximize spectrum efficiency, which is typically a limited resource, cellular networks are adapted to produce real-time event messages. An event message is a measurement report sent between different components in the cellular network (e.g., RNC, Node B, UE, etc). Event messages can be categorized to several types depends on the types of measurements encapsulated within, and on the network components participating in the messaging.
The measurement reports are transferred through many types of messages including RRC (Radio Resource Control) protocol messages, NBAP (Node B Application Protocol) messages, and frame protocol messages. The different reports include a wide variety of parameters measurements, for example, traffic volume, channel quality, propagation delay, carrier power, path loss, and many more. The number of different parameters measured and reported reaches several hundreds in a typical cellular system. Ericsson (“Real-time performance monitoring and optimization of cellular systems”, Per Gust.s, Per Magnusson, Jan Oom and Niclas Storm, First published in Ericsson Review no. 01, 2002) discloses a real-time optimization of a radio access network utilizing the system event messages. However, Ericsson as other providers utilizes real-time event messages for monitoring performance and system optimization, and not for radiation control.
None of the currently available techniques provide a satisfying solution to the problem of managing and controlling radiation sources. Therefore, there is a need for a system that provides a continuous monitoring of radiation sources, which incorporates the important benefits of prior art techniques, and allows accurate measurement and calculation of radiation coming from different sources for detecting radiation anomaly in real time.
It is therefore an object of the present invention to provide a system for automatically and continuously managing and controlling wireless radio telecommunication non-ionizing radiation sources.
Another object of the present invention is to provide a system for guaranteeing that cellular network operators are subjected to governmental laws and regulations.
Another object of the present invention is to accurately calculate the percentage of radiation level anomalies at cellular sites.
Another object of the present invention is to provide a system for detecting radiation anomaly in real time, and decreasing the average time for treating the radiation anomaly.
Another object of the present invention is to immediately discover the source of the radiation anomaly.
Yet another object of the present invention is to provide a cost-effective system for detecting radiation anomaly.
Other objects and advantages of the invention will become apparent as the description proceeds.